Stabilizing strut, in particular for a chassis of a vehicle, and method for the production thereof

ABSTRACT

A stabilizing strut, in particular for a chassis of a vehicle, in particular a Watt strut, is described, the strut having an elongate strut body which is designed as a profile. The strut body is formed as a profile which is open on one side at least in some sections along its longitudinal direction and the two longitudinal edges of which are connected integrally to each other at least in some sections axially to give a closed profile. Furthermore, a method for producing a stabilizing strut of this type is described.

CROSS REFERENCE TO PENDING APPLICATION

The present application is a continuation of pending internationalpatent application PCT/EP01/03382 filed on Mar. 24, 2002 whichdesignates the United States, and which claims priority of German patentapplication 100 14 581.7 filed on Mar. 27, 2000.

BACKGROUND OF THE INVENTION

The invention relates to a stabilizing strut, in particular for achassis of a vehicle, in particular a Watt strut, having an elongatestrut body which is designed as a profile.

The invention relates furthermore to a method for producing astabilizing strut of this type, a strut body being formed from asheet-like blank to give a profile.

A stabilizing strut of this type and a method for the production thereofare known in general through their use or application.

A special stabilizing strut which is used in many chassis of vehicles isthe Watt strut. The Watt strut is part of the Watt linkage which is usedprimarily in vehicles having a rigid axle, in order to reduce lateralmovements of the rigid axle. In the case of the Watt linkage, a lever,which is mounted rotatably in the center, is mounted, for example, onthe differential and is guided to both sides by a respective stabilizingstrut or Watt strut which is identical in length and is fastened to thevehicle body. This coupling means that only an exact, vertical movementof the guided lever is possible.

However, the invention is not restricted to a Watt strut.

The stabilizing struts known to date have an elongate strut body whichis designed as a profile.

The strut body of the known stabilizing struts is designed as a singlepart in the longitudinal direction of the strut body. In thecircumferential direction, the strut body of the known stabilizingstruts is designed as two parts. The profile of the known stabilizingstruts is, as a rule, a circumferentially closed box profile, having abase section which is formed in a U-shape in cross section, the openside of the U being closed by a cover plate which extends over theentire length of the strut body. A profile of this type, which is closedon all sides, ensures the flexural rigidity required for a stabilizingstrut of this type. Other known designs of stabilizing struts are pipeswhich are continuously and circumferentially closed.

A disadvantage of the known stabilizing struts is that they have a highweight because of the design described above, and, since the cover platehas to be welded or soldered to the base profile over the entire axiallength, the production method is also time-consuming and costly in termsof material and is consequently expensive. A further disadvantage isthat surface engineering cannot be used properly in the interior of thestabilizing strut. For example, the inside of the closed profile cannotbe coated and so there is an increased risk of corrosion.

The invention is therefore based on the object of developing astabilizing strut, and a method for the production thereof, of the typementioned at the outset to the effect that the stabilizing strut islower in weight in spite of the flexural rigidity being ensured, theproduction method can be carried out at less expense, and surfaceengineering can readily be used on the inside.

SUMMARY OF THE INVENTION

With regard to the stabilizing strut mentioned at the outset, thisobject is achieved in that the strut body is formed as a profile which,in cross section, is open on one side at least in some sections alongits longitudinal direction and the two longitudinal edges of which areconnected integrally to each other at least in some axial sections togive a closed profile.

In the case of the method, the object underlying the invention isachieved according to the invention in that the strut body is initiallyformed to give a profile which, in cross section, is open on one side,and the longitudinal edges of which are connected integrally to eachother at least in some axial sections to give a closed profile.

The stabilizing strut according to the invention breaks away from theconcept of the known stabilizing struts—of forming a box profile whichis closed continuously axially and has a bottom part and a separatecovering part or as a pipe. Instead, the stabilizing strut according tothe invention is produced by forming a profile which is open on one sideand is circumferentially closed in some axial sections and therefore inaxially limited portions only. In contrast to the known stabilizingstruts, in which the base box profile is closed by a separate coveringplate, so that the strut body of the known stabilizing struts consistsof a number of parts in the circumferential direction, in the case ofthe stabilizing strut according to the invention, the closed sections ofthe strut body are in the manner of a single part in the circumferentialdirection by the two longitudinal edges being connected integrally inthese regions to give the closed profile. The stabilizing strutaccording to the invention is therefore, first, low in weight, but thedesign as a profile which is closed in some sections axially issimultaneously flexurally rigid. The production method according to theinvention is less time-consuming, is material-saving and thereforecost-effective, and the inside of the profile can readily be treated atany time.

In a preferred refinement of the stabilizing strut, the longitudinaledges are connected by means of at least one link which extends in partaxially in the longitudinal direction of the strut body and is formedintegrally onto at least one of the longitudinal edges.

This measure constitutes a particularly favorable possibility in termsof production of connecting the two longitudinal edges integrally toeach other in some axial sections to give a closed profile. The at leastone link, preferably the plurality of links distributed in thelongitudinal direction of the stabilizing strut, contributes toincreasing the flexural rigidity of the stabilizing strut according tothe invention, and, nevertheless, weight is saved by limiting the linksaxially.

Within the scope of this refinement, a respective link canadvantageously be formed onto the two longitudinal edges, with theresult that the two links lie opposite each other and are connected toeach other between the longitudinal edges. However, the link may also beformed integrally onto the one longitudinal edge, protrude as far as theopposite longitudinal edge and be connected to the latter, with theresult that in the overlapping region of the link with the oppositelongitudinal edge a classical fillet weld joint can advantageously beused.

In a further preferred refinement, the at least one link runstransversely or obliquely to the longitudinal direction of the strutbody in the manner of a web.

It is furthermore preferred if there are at least two links which form aV with one another.

This arrangement of the links enables the flexural rigidity of thestabilizing strut to be improved even further because tensile orcompressive loads acting in different directions can be better absorbedby the V-shaped arrangement of the links. In this connection, aplurality of links in the form of a number of Vs may form a zigzagarrangement.

According to a further preferred refinement, the at least one link mayalso be of curved design, the link being formed on at two axiallyspaced-apart points on the same longitudinal edge of the strut body.

Within the context of the present invention, in addition to thepreviously mentioned exemplary refinements, further refinements for theone or more links can be taken into consideration, which refinementscorrespondingly contribute to increasing the flexural rigidity of thestabilizing strut.

The connection of the longitudinal edges of the strut body by means ofat least one link is particularly advantageous if the strut body isproduced as a punched part, the at least one link being formed by thepunching process, by material being left on one of the longitudinaledges.

In the case of the method according to the invention, to this end thesheet-like blank is manufactured as a punched part onto which at leastone link is formed during the punching process, by material being left,the link being used to connect the longitudinal edges of the strut bodyto each other after the forming process to give the profile.

These measures enable the stabilizing strut according to the inventionto be produced with just a few manufacturing steps, namely punching,forming to give the profile, if appropriate bending of the at least onelink and connecting of the two longitudinal edges of the strut body viathe at least one link. Any known method, for example welding, solderingor bonding, may be used as connecting techniques.

In a further preferred refinement, the strut body is formed, at least insome axial sections, essentially as a U-profile which is closed in someaxial sections by connecting the longitudinal edges.

This produces a box profile which is closed axially only in somesections and which has a particularly high flexural rigidity.

In a particularly simple refinement of the stabilizing strut accordingto the invention, the strut body is formed, at least in some axialsections, essentially as a profile which is triangular in cross sectionand is closed at the longitudinal edges by direct connection of thelongitudinal edges. In open regions, the profile can then, for example,be U-shaped in cross section.

In this refinement, a stabilizing strut which is advantageouslyparticularly low in weight and can be produced particularlycost-effectively is produced, which strut can be manufactured from asimple, rectangular, sheet-like blank by a single forming process withsubsequent, sectional or continuous joining of the longitudinal edges.

In a further preferred refinement, the strut body differs in crosssection with regard to shape and/or cross-sectional size in thelongitudinal direction.

By means of cross-sectional changes of this type, for example expansionsof the cross section at various points of the strut body, the flexuralrigidity can be further increased. Also, for example in conjunction withthe previously mentioned refinements, the strut body may in somesections have a U-shaped profile and in some sections a profile which istriangular in cross section, by means of direct connection of thelongitudinal edges.

In a further preferred refinement of the stabilizing strut according tothe invention, a respective bearing bushing is arranged at thelongitudinal ends of the strut body.

If the bearing bushings are formed integrally, the entire stabilizingstrut can be manufactured in a particularly simple manner as a singlepart from a blank by punching, forming and joining. However, the bearingbushings may also be subsequently joined on separately in the form ofpieces of pipe, for example by welding.

In a further preferred refinement, the strut body is composed in thelongitudinal direction from at least two profile parts which arearranged partially overlapping one another in the longitudinal directionand are connected to one another in the overlapping region.

In this case, although a multi-part design is accepted in thelongitudinal direction of the strut body, said design has the advantagethat bearing bushings arranged at the longitudinal ends of the assembledstrut body can have bearing axes which are not parallel to one another.This may be advantageous for structural reasons of the chassis, intowhich the stabilizing strut is to be fitted, because the predetermined,spatial conditions can be better used in this manner. This cannot easilybe achieved with the conventional designs mentioned at the beginning.The multi-part design of the strut body in the axial direction enablesthe individual profile parts to be joined to one another with an angularoffset, as a result of which a non-rectilinear stabilizing strut canthereby be produced.

In this case, the profile parts may be joined, with their respectiveopen side pointing in the same direction; it is likewise preferred ifthe profile parts are joined, with their respective opening sidepointing in the opposite direction, to give the strut body.

In the case of the latter refinement, a profile which iscircumferentially closed is produced in the overlapping region of theprofile parts, as a result of which the flexural rigidity can beincreased even further.

Further advantages and features arise from the following description andthe attached drawing.

It goes without saying that the features mentioned above and those whichare yet to be explained below can be used not only in the respectivelyindicated combination, but also in other combinations or on their own,without departing from the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are illustrated in the drawingand will be described in greater detail below with reference thereto. Inthese drawings:

FIG. 1 shows an interrupted overall illustration of a stabilizing strutin plan view;

FIG. 2 shows a detail of the stabilizing strut in FIG. 1 in side view;

FIG. 3 shows a section along the line III—III in FIG. 1;

FIG. 4 shows a section along the line IV—IV in FIG. 1;

FIG. 4a shows a sectional illustration comparable to FIG. 4, accordingto an exemplary embodiment modified in comparison with FIG. 1;

FIG. 5 shows a sectional illustration comparable to FIG. 3, according toan exemplary embodiment modified in comparison with FIG. 1;

FIG. 6 shows a detail of a stabilizing strut according to a furtherexemplary embodiment in plan view;

FIG. 7 shows another exemplary embodiment of a stabilizing strut in planview;

FIG. 8 shows another exemplary embodiment of a stabilizing strut in planview; and

FIG. 9 shows a section along the line IX—IX in FIG. 8.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In FIGS. 1 through 4, a stabilizing strut provided with the generalreference number 10 is illustrated. The stabilizing strut 10 is used asa Watt strut in a chassis of a vehicle.

The stabilizing strut 10 has an elongate strut body 12 which is designedas a profile.

The strut body 12 is joined in the longitudinal direction of the strutbody 12 from at least two profile parts 14 and 16 which are arrangedpartially overlapping one another in the longitudinal direction of thestrut body 12, in an overlapping region referred to by A, and areconnected to one another. For this purpose, an axial end section 18 ofthe first profile part 14 is inserted into an axial end section 20 ofthe second profile part 16. The axial end section 20 of the secondprofile part 16 is correspondingly formed with a widened cross section.Conversely, the axial end section 18 of the first profile part 14 could,however, also be formed with a cross section which is reduced incomparison with the rest of the profile part 14.

The axial end section 18 and the axial end section 20 are connected toeach other with a cohesive material joint via plug welds 22, 24 or viaflanged edge welds 23 and 25 and via a plug weld 26 and via a filletweld 27 (cf. also FIG. 3).

While, in FIG. 1, the profile parts 14 and 16 are arranged in arectilinear orientation with respect to each other in the longitudinaldirection of the strut body 12, the profile parts 14 and 16, owing tothe multi-part design in the longitudinal direction, may also be joinedto each other with an angular offset, with the result that in such acase, the strut body 12 does not assume a rectilinear profile, but abent profile.

At the end lying opposite the axial end section 18 the first profilepart 14 has a bearing bushing 28 with a bearing opening 29.Correspondingly, the second profile part 16 has a bearing bushing 30with a corresponding bearing opening (not illustrated) at its end lyingopposite the axial end section 20.

The bearing bushings 28 and 30 can be formed integrally onto the profilepart 14 and 16, respectively, or can be welded on as pieces of pipe oras punched parts.

In the exemplary embodiment shown, bearing axes 32 and 34, which aredrawn in in FIG. 1, run parallel to each other, but, owing to themulti-part design of the strut body 12 in the longitudinal direction, asdescribed above, because of a corresponding angular offset of theprofile parts 16 and 14 with respect to each other, the bearing axes 32and 34 may also not run parallel to each other, if a stabilizing strutof this type is desired because of structural conditions of the vehicle,it also being possible to achieve this with a rectilinear orientation ofthe profile parts 14 and 16, if the bearing bushings 28 and 30 are notformed onto the strut body 12 at right angles thereto.

However, the invention is not restricted to a multi-part design of thestabilizing strut 10 in the longitudinal direction of the strut body 12;rather, the stabilizing strut 10 may also be designed as a single pieceor integrally in the longitudinal direction.

The strut body 12 is formed in cross section as a profile which is openon one side at least in some axial sections along its longitudinaldirection. As is revealed in FIGS. 3 and 4, the strut body 12 is shapedessentially as a U-profile which has a base section 36 and two wallsections 38 and 40 running transversely thereto. As illustrated in FIGS.1 and 2, punched holes 39 and 41 are formed in the base section and inthe wall sections 38 and 40, as a result of which a further reduction inweight is achieved, but the flexural rigidity is not impaired.

In contrast to FIG. 1, the profile may also have differentcross-sectional shapes and different cross-sectional sizes, as seen inthe longitudinal direction, for example expansions or taperings. Theflexural rigidity can thereby be further improved by expansions orpulled-in areas.

The strut body 12 is open on one side in some axial sections in crosssection, i.e. in the circumferential direction, longitudinal edges 42and 44 of the strut body 12, which constitute free ends of the wallsections 38 and 40, being connected integrally to each other in someaxial sections to give a closed profile. The longitudinal edges 42 and44 are designated for the profile part 16 by way of example, it beingunderstood as self-evident that the profile part 14 also haslongitudinal edges of this type.

The profile parts 14 and 16 are in each case designed as a single part.The integral connection of the longitudinal edges 42 and 44 is realizedby at least one link, and in the exemplary embodiment shown by aplurality of links 46 which are formed integrally onto at least one ofthe longitudinal edges 42 or 44.

In the exemplary embodiment shown according to FIGS. 1 to 4, a link 46is formed integrally onto the longitudinal edge 42 and a link 48 ontothe longitudinal edge 44, the links 46 and 48 lying opposite each otherand being joined between the longitudinal edges 42 and 44 via a weld 50or a soldered seam or via another connecting method.

A plurality of such pairs of links 46 and 48 are distributed in thelongitudinal direction of the strut body 12, with the result that thestrut body 12 constitutes a closed profile in the regions in which thelinks 46 and 48 are present.

In this case, the pairs of links 46 and 48 form webs runningtransversely to the longitudinal direction of the strut body 12.

However, webs of this type may also run obliquely to the longitudinaldirection of the strut body 12, as will be described later on withreference to another exemplary embodiment.

FIG. 4a illustrates an exemplary embodiment which is slightly modifiedin comparison with FIGS. 1 to 4, in which the at least one link 46′ isformed integrally onto the longitudinal edge 44′ of the wall section 40′while the free end of the link 46′ is welded to the oppositelongitudinal edge 42′ via a fillet weld 43′. For this purpose, the freeend of the link 46′ protrudes laterally slightly over the longitudinaledge 42′, as a result of which the fillet weld 43′ can easily be putinto place.

The first profile part 14 and the second profile part 16 are produced ineach case as punched parts, the links 46 and 48 being left on thelongitudinal edges 42 and 44, respectively, by the punching process,when punching out from a sheet-like blank.

In the case of an overall single-part design of the strut body 12, thelatter can therefore be produced cost-effectively with littleexpenditure of time from a single, sheet-like blank by punching, formingto give the profile and connecting the links 46 and 48 with a cohesivematerial joint.

Similarly, the bearing bushings 28 and 30 may, as already mentioned, beconnected integrally to the strut body 12 during the above-describedpunching process from the sheet-like blank.

In the case of a method for producing the stabilizing strut 10, thelatter can therefore be formed from a sheet-like blank to give a profileby the strut body 12 being formed to give a profile which is open on oneside in the longitudinal direction, and the longitudinal edges 42 and 44of which are connected integrally to each other at least in some axialsections to give a closed profile, specifically, in the exemplaryembodiment shown, by means of the links 46 and 48 which, prior to beingjoined, are likewise bent in the forming process, in which the U-profileis formed, into the corresponding position according to FIG. 4.

As likewise already mentioned, during the production process the links46 and 48 are formed onto the sheet-like blank during the punchingprocess, by material being left.

In the case of the two-part design of the stabilizing strut 10 in thelongitudinal direction of the strut body 12 with a first profile part 14and a second profile part 16, the two profile parts 14 and 16, afterbeing completed, are overlapped by their axial end sections 18 and 20,as shown in FIG. 1, and are joined by the plug welds 22, 24 and 26 andthe fillet weld 27.

While, according to FIG. 3, the profile parts 14 and 16 are joined, withtheir respective open side pointing in the same direction, to give thestrut body 12, in FIG. 5, in an exemplary embodiment modified withrespect thereto, the profile part 14′ and the profile part 16′ arejoined with their respective open side pointing in the oppositedirection, to give the strut body 12′. In the overlapping region A ofthe profile parts 14′ and 16′, a profile, which is closed in some axialsections, of the strut body 12′ is therefore produced. Instead of theplug weld 26 on the base side of FIG. 3, the profile parts 14′ and 16′are welded to each other via flanged edge welds 52 and 53, and thelateral plug welds 22 and 24 in FIG. 3 are shifted further downward inFIG. 5.

FIGS. 6 and 7 illustrate modifications of the geometrical arrangementand design of the links 46 and 48 in FIGS. 1 to 4.

FIG. 6 illustrates a link arrangement consisting of three links 54, 56and 58 which together define a V. The link 54 is joined to the links 56and 58 at welds 60 and 62.

The same V-shaped arrangement may also be obtained if there were onlytwo links which are both formed integrally onto the longitudinal edge44′, point in the manner of a V in opposite directions obliquely to thelongitudinal direction of the longitudinal edge 44′ and arecorrespondingly welded to the opposite longitudinal edge 42′. However,the links 56 and 58 may also be designed in the same manner as the link54, as indicated by broken lines, so that overall a continuous zigzagarrangement of links is produced and a high flexural rigidity isobtained.

FIG. 7 illustrates a link arrangement which is formed from links 64, 66and 68 of curved design, each of the links 64, 66 and 68, as shown forthe link 64, being formed integrally on at two axially spaced-apartpoints on the same longitudinal edge 42′. On the opposite longitudinaledge 44′, the links 64, 66 and 68 are welded by their crowns 70 to thelongitudinal edge 44′.

Respectively adjacent links 64 and 66 or 64 and 68 are likewise weldedto each other at contact points 72 or 74, respectively.

The preceding exemplary embodiments show that there are diversepossibilities within the context of the invention for the design of alink connection of the longitudinal edges of the profile which is openon one side.

Finally, FIGS. 8 and 9 illustrate a further exemplary embodiment of astabilizing strut 80 which differs from the preceding exemplaryembodiments by its strut body 82 being formed essentially as a profilewhich is triangular in cross section and is connected at longitudinaledges 84 and 86 by direct connection of the longitudinal edges 84 and86.

A profile of this type can likewise be formed from a sheet-like blank bya forming process to give the triangular profile cross section, in whichcase subsequently the longitudinal edges 84 and 86 are connected to eachother at least in some sections by a weld. In this manner, a completelyclosed box profile is realized which, overall, is integral or is asingle part, and can therefore be produced cost-effectively and with alow expenditure on time.

In a modification of this refinement, the profile may, in some sections,also be of U-shaped design in cross section and may be deformed, bydirect connection of the longitudinal edges 84 and 86 only in somesections, to give the triangular cross section illustrated.

What is claimed is:
 1. A stabilizing strut for a chassis of a vehicle,comprising an elongate strut body formed from a sheet-like blank andhaving a first end and a second end and being formed into a profile,said profile, in cross section, being open on one longitudinal side atleast in some axial sections along a longitudinal direction of saidprofile, and having two longitudinal edges which are joined integrallyto each other, at least in some axial sections of said profile, to givein circumferential direction a single part closed profile in said someaxial sections; wherein said strut body is joined in said longitudinaldirection from at least two profile parts which are arranged partiallyoverlapping one another in said longitudinal direction and are connectedto one another in said overlapping region.
 2. The stabilizing strut ofclaim 1, wherein said profile parts are joined, with their respectiveopen side pointing in the same direction, to form said strut body. 3.The stabilizing strut of claim 1, wherein said profile parts are joined,with their respective opening side pointing in the opposite direction,to from said strut body.
 4. The stabilizing strut of claim 3, whereinsaid strut body is formed, at least in some axial sections, essentiallyas a U-profile which is closed in some axial sections.
 5. Thestabilizing strut of claim 1, wherein said strut body differs in crosssection with regard to shape in said longitudinal direction.
 6. Thestabilizing strut of claim 1, wherein said strut body differs in crosssection with regard to cross-sectional size in said longitudinaldirection.
 7. The stabilizing strut of claim 1, wherein a respectivebearing bushing is arranged at longitudinal ends of said strut body.